Antihistamines are a well known class of pharmaceutically active compounds, some of which are described in U.S. Pat. Nos. 5,869,479, 5,691,370 and Remington's 20th Ed., pages 1464-1470 which are incorporated herein by reference.
Piperidinoalkanol derivatives which are disclosed in U.S. Pat. No. 4,996,061 and incorporated herein by reference are a particular class of antihistamine. Loratadine is a specific type of piperidinoalkanol and is disclosed in U.S. Pat. No. 4,282,233 as an antihistamine with little or no sedative effect. Schering Corporation currently markets a rapidly disintegrating form of loratadine under the tradename CLARITIN REDITABS. CLARITIN REDITABS contain 10 mg of micronized loratadine and disintegrate in the mouth within seconds after placement on the tongue, allowing its contents to be subsequently swallowed with or without water. CLARITIN REDITABS also contain citric acid, gelatin, mannitol and mint flavoring. See Physicians' Desk Reference, 52nd Ed., pp. 2613-2615.
Another antihistamine is the active metabolite of loratadine, known as descarboethoxyloratadine. Descarboethoxyloratadine is disclosed in U.S. Pat. No. 4,659,716 and is prepared by the removal of the carboethoxy moiety from the loratadine molecule. Still other antihistamines that are known and can be used in the present invention are astemizole, azatadine, cetirizine, fexofenadine and pharmaceutically acceptable salts of these compounds.
Rapidly disintegrating dosage formulations are known in the art. Some rapidly disintegrating dosage formulations are described in U.S. Pat. Nos. 4,371,516; 5,298,261; 5,587,180; 5,720,974; 5,807,576; 5,866,163; 5,869,098 and 6,048,541 which are incorporated herein by reference. The prior art rapidly disintegrating formulations require complicated processing techniques such as lyophilazation foam techniques or specialized excipients.
It is therefore an objective of the present invention to provide a safe and effective rapidly disintegrating oral antihistamine dosage formulation that can be economically be prepared.